National Board Dental Hygiene Examination (NBDHE) Dental Hygienist Practice Test

The trigeminal nerve is responsible for innervating which of the following structures?

1. Muscles of facial expression

2. Muscles of mastication

3. Taste buds on the anterior tongue

4. Salivary glands

The correct answer is: Muscles of mastication

The trigeminal nerve, specifically its motor branches, plays a crucial role in innervating the muscles of mastication. This nerve is the fifth cranial nerve and is primarily responsible for sensory functions related to the face, but it also has a significant motor component that innervates key muscles involved in chewing, such as the masseter, temporalis, and pterygoid muscles. Understanding this anatomy is fundamental for dental hygienists, as it helps in comprehending how the muscles and nerves interact during oral procedures and the implications in cases of nerve injury or dysfunction. While the other answer choices include important anatomical structures, they do not pertain to the trigeminal nerve’s function in muscle innervation. The muscles of facial expression are innervated by the facial nerve, taste sensation on the anterior tongue is provided by the facial nerve's chorda tympani branch, and salivary glands receive autonomic innervation primarily from the facial nerve and glossopharyngeal nerve, rather than the trigeminal nerve. This differentiation reinforces the understanding of the origins and functions of cranial nerves relevant to dental hygiene practices.